Upon completion of Work No. 1, the new channel comprised in that work shall be treated as part of a main river within the meaning given in Part IV of the Act of 1991, the former channels of the river diverted by the works shall cease to be treated as part of a main river and the main river map for the area shall be varied to give effect to this subsection.

For the purposes of subsection (1) above, the Rivers Authority shall apply for and the Minister of Agriculture, Fisheries and Food shall make any necessary variation of a main river map.

Section 194 (5) of the Act of 1991 shall not apply to any variation of a main river map made under this section.